…-e0c9e98b

refactor: use file scoped namespaces

This PR modernizes the C# codebase by converting all traditional block-style namespace declarations to file-scoped namespace syntax. This change flattens the file structure, removes unnecessary indentation levels, and aligns the code with the latest C# conventions.

- Use File Scoped `namespace`s instead of typical `namespace`s: Many source files originally declared block-scoped namespaces with braces, causing extra nesting and indentation. Each file has been updated to use the file-scoped namespace syntax (ending with a semicolon), and the `using` directives and class/record declarations have been moved to the top of the file. This refactor improves readability and consistency across the project.

> This Autofix was generated by AI. Please review the change before merging.

This PR refactors lambda expressions that contain only a single statement to use more concise, expression-bodied forms and improves readability across chained calls.

- Consider simplifying lambda when its body has a single statement: The original code used a block lambda for an async call and a tightly coupled Setup expression. In the first patch, the `Setup(a => a.GetLatestVersion(...))` call is reformatted across multiple lines for clarity while retaining its expression-bodied form. In the second patch, the multi-line block inside `Should.NotThrow(async () => { await ... })` is converted into an inline, expression-bodied async lambda, removing unnecessary braces and making the code more succinct.

> This Autofix was generated by AI. Please review the change before merging.

…-9ce2dbf5

refactor: use file scoped namespaces

This PR renames the child class to prevent name collisions with its parent class.
- Child and parent classes cannot share the same name: The issue arose because the subclass "DockerHelper" shared the exact name with its base class, leading to ambiguity and compilation errors. We addressed this by renaming the subclass to "CallbackHandlerDockerHelper", clearly distinguishing it from the parent.

> This Autofix was generated by AI. Please review the change before merging.

…-4a8f08f9

refactor: rename DockerHelper subclass to CallbackHandlerDockerHelper

This PR refactors the code to comply with the guideline of having a single public class per namespace. It removes an unintended BOM character, standardizes brace placement, and adds missing closing braces to properly scope classes within their namespaces.

- Consider having 1 `public` class per namespace: DeepSource flagged that having multiple public classes in a single namespace can lead to tangled code organization and lower maintainability. The patch removes a hidden BOM character in the using directive that was causing inconsistent file encoding. It also standardizes opening brace placement and adds missing closing braces to ensure each public class is scoped within its own namespace.

> This Autofix was generated by AI. Please review the change before merging.

This PR reorganizes the code by encapsulating all classes within the `CallbackHandler.IntegrationTests.Common` namespace, aligning with C# best practices and improving code maintainability and scope management.

- Classes and structs should be declared within a `namespace`: DeepSource flagged that several classes (`GenericSteps`, `TestingContext`, `Setup`) were declared at the file root without a namespace. We introduced the `CallbackHandler.IntegrationTests.Common` namespace and wrapped these class definitions inside it, updating indentation and braces to ensure proper encapsulation and readability.

> This Autofix was generated by AI. Please review the change before merging.

…-cd47f680

refactor: enforce one public class per namespace